Information flow has increased substantially in recent years, and networks have evolved to accommodate not only a greater number of users but also higher data rates. An example of a relatively high speed network is the subject of ANSI/IEEE Standard 802.5 which provides a description of the peer-to-peer protocol procedures that are defined for the transfer of information and control between any pair of Data Link Layer service access points on a 4 Mbit/s Local Area Network with token ring access. At such data rates, however, wiring paths themselves become antennae that both broadcast and receive electromagnetic radiation. This is a problem that is aggravated when station hardware requires multiple wire-pairs. Signal coupling (crosstalk) between different pairs of wires is a source of interference that degrades the ability to process incoming signals. This is manifested quantitatively as decreased signal-to-noise ratio and, ultimately, as increased error rate. Accordingly, crosstalk becomes an increasingly significant concern in electrical equipment design as the frequency of interfering signals is increased.
Crosstalk occurs not only in the cables that carry the data signals over long distances, but also in the connectors that are used to connect station hardware to the cables. ANSI/IEEE Standard 802.5 discloses a Medium Interface Connector having acceptable crosstalk rejection at the frequencies of interest. This Connector features four signal contacts with a ground contact, and is hermaphroditic in design so that two identical units will mate when oriented 180 degrees with respect to each other. This Connector is available as IBM Part No. 8310574 or as Anixter Part No. 075849. Crosstalk rejection appears to result from short connector paths, ground shields, and the selection of particular terminals for each wire-pair. As might be expected, such connector arrangements are relatively expensive and represent a departure from communication plugs and jacks such as specified in Subpart F of the FCC Part 68.500 Registration Rules and used in telecommunication applications.
For reasons of economy, convenience and standardization, it is desirable to extend the utility of the above-mentioned telecommunication plugs and jacks by using them at higher and higher data rates. Unfortunately, such plugs and jacks include up to eight wires that are close together and parallel--a condition that leads to excessive crosstalk, even over relatively short distances. Attempts to improve this condition are complicated by the fact that an assignment of particular wire-pairs to particular terminals already exists which is both standard and non-optimum. Indeed, in ANSI/EIA/TIA-568 standard, the terminal assignment for wire-pair 1 is straddled by the terminal assignment for wire-pair 2 or 3. If the electrical conductors that interconnect with these terminals are close together for any distance, as is the case in present designs, then crosstalk between these wire-pairs is particularly troublesome. Accordingly, it is desirable to reduce crosstalk in electrical connectors such as the plugs and jacks commonly used in telecommunication equipment.